Electrode for electric-arc lamps.



A. D. JONES. ELECTRODE FOR ELECTRIC ARC LAMPS. APELIGATION TILEDAPR.1B,1908. RENEWED OUT.11,1909.

944, 1 39. Patented Dec. 21. 1909 Fig.1.

UNITED STATES Parana. OFFICE.

ADRIAN DENMAN JONES, OF HOLLOWAY, LONDON, ENGLAND.

I ELECTRODE FOR ELECTRIC-ARC LAMPS.

Specification of Letters Patent.

Patented Dec. 21, 1909.

Application filed April; 18, 1908, Serial No. 427,824. Renewed Octoberll, 1909. Serial No. 522,124.

To all whom it may concemf Be it known that I, ADRIAN Damian JONES, a subject of the King of Gri eat Britain and Ireland, and residing at Hartham orks, Hartham Road, Holloway, London, N., England, have invented certain new and useful Improvements, in Electrodes for Elec' tric-ArcIlamps, of which the following is a specification.

My invent on relates to electrodes particularly adapted for use in electric arc lamps 'of the inclosed type in which the arc is vapors inthe arc to a high. degree of iii-'- candescence giving a high light etficiency. I have also found that it is. desirable to add salts having a high-melting 'point and for this reason it is desirable to add a steadying salt which acts as a flux in melting the chemicals to form a uniform liquid before vaporization. I find that with such mixtures no liquid slags are formed and therefore the troubles caused in other lamps in which chemicals are used are completely avoided.

My invention consists in electrodes carrying a mixture of salts of high melting point andhigh vapor density and so arranged relatively to the carbon that a good contact can always be obtained by placing the ends of the electrodes together;

My invention further consists in compound electrodes for electric arc lamps carrying a mixture of calcium tungstate and calcium fluorid with the addition of sodium or potassium salts.

The invention consists more specifically in compound carbons for inclosed electric arc lamps containing a mixture of calcium fiuorid, calcium tungstate and sodium tungstate or potassium sulfate.

' The invention also consists in arranging the chemicals in flutings in the carbons so that a solid core of carbon is always provided and enables a good contact to be made throu h the electrodes whenever they are placed together.

Referring to the accompanying drawings, Figure 1 shows an elevation, and Fig. 2 a horizontal section of an electrode according to my invention.

In carrying the invention into effect according to one modification I form the carbon with a central core, (1, having hollow flutings, b, sur1 oundi ng it. Both carbons for an arc lamp may be formed in asimilar manner or if only one carbon is to contain chemicals the positive carbon should be the one so formed.

The flutings in the carbon of the electrode are filled up with a mixture of chemicals held together and bound to the carbon by means of any suitable binder such as dcxtrin.

solution. For the purpose of the paste I form a mixture of one part of calcium tungstate and one part of calcium tluorid and with this I- mix one half part of sodium tungstate or potassium sulfate. With electrodes of this kind when used in an inclosed arc lamp the are formed is long and narrowand with a current of 5 amperes at 70 volts may be one inch long and is quite thin. The electrodes may be of considerable dimensions and the positive electrode is preferably placed at the bottom. The electrodes are preferably used in an inclosure of the kind described in my Patent No. 935,518, issued Sept. 28, 1909.

In an arc lamp having the carbons fluted as described the lower carbon tends to burn away to a point and the point will therefore always consist of pure carbon so that when the arc is'broken and the electrodes are again brought together there will be a contact of pure carbon between the positive and,

.nosity given by either separately. The object of the addition of the sodium tungstate or potassium sulfate is to steady the arc, and I find that the mixture I have above described gives extremely satisfactory results as thearc retain'sits color and eificiency and lamps carrying a mixture of calcium rung-- burns steadily in inclosurs shut oil from state, calcium fluorid anda steadying salt atmospheric air. of an alkali metal, as set forth. I

Having thus described my invention what In testimony whereof, I aflix my signa- '5 I claim as new and desire to secure by Let-'1 ture inpresence of two Witnesses.

ters Patent is:".v a 4 a 1. Compound electrodes for electric arc AD DENMAN lamps carrying a mixture'of calcium tung- Witnesses: state and'calcium fiuorid, as set forth. W. G. BISHOP DOWLING, 10 2. Compound electrodes for electric arc H, D. JAMESON. 

